According to the FDA, people who already have liver problems, or who take medications that can harm the liver, should ask a doctor before taking kava. Kava users should consult a doctor if they experience any possible symptoms of liver disease. Those include: jaundice, or yellowing of the skin or eyes; brown urine; nausea or vomiting; light-colored stools; unusual tiredness or weakness; stomach or abdominal pain, or loss of appetite.

Taking large amounts of kava may slow the heart. Do
not take Kava Kava if you are: Pregnant, Lactating, or suffering from Endogenous depression.

Not recommended for persons with Parkinson's disease. Caution should be taken when operating machinery or driving when using higher doses.